This invention relates to a gored packing bag provided with an opening and closing fastener on an opened portion thereof. When a batch of contents such as powdered beverages, e.g., cocoa are taken out from a packing bag, an opened portion thereof is repeatedly opened and closed and should desirably be provided with an opening and closing fastener. Conventionally known is a flat vinyl packing bag without gores or bellows which is provided with an intermeshing fastener on both inner surfaces of face and back bodies so as to freely open and close an opened portion thereof. There has also been proposed a gored packing bag which can keep a larger amount of contents. In such a gored packing bag, however, a fastener is hardly attached or, even if it is attached, a free play of gores is suppressed around the fastener. As the fastener can be attached only between inner ends of gores, length of the opened portion is decreased when the width of gores is increased to keep a larger amount of contents and vice versa, the longer the opened portion, the shorter the gores become and the lesser an effect of gores is exhibited.
As to a method for producing the above mentioned packing bag, as shown in FIG. 9, a bag body and a fastener portion are independently manufactured and then integrated. This increases unfavorably not only numbers of parts but production steps of the bag and reduces productivity thereof, thereby increasing the production cost as a whole.